Sharks have been given a bad reputation by the media over the years. But at most dive sites, they are very rarely spotted by divers, and even when they are, they usually avoid divers or ignore them.
We are not on the menu for sharks. However (as with any wild animal), respect should always be shown when you dive with sharks. If you are scared of seeing sharks, you can research which areas of the world you are less likely to see them and dive there.